Palos Verdes Shelf Superfund Site

U.S. ENVIRONMENTA L P ROTECTION A GENCY $ REGION 9 $ S AN FRANCISCO, CA $ F EBRUA RY 2008 Remedial Investigation Report Completed; Feasibility Study Underway The Palos Verdes Shelf Superfund site is an area of con­ taminated sediment off the Palos Verdes Peninsula. The contaminated sediment lies in the Pacific Ocean at depths of 150 ft. and more, too deep for human contact. However, the fish found in the Palos Verdes Shelf area contain high con­ centrations of DDT and PCBs. Although current concentra­ tions have dropped from historical highs, concentrations of DDT and Remedial PCBs in fish continue to pose a threat to human health and the natu­ ral environment. Investigation Report At-A-Glance

118 30’ 118 20’ The Remedial Investigation (RI) summa­ Santa Monica Bay rizes: 33 50’ LOS ANGELES COUNTY $ the nature and extent of contamination, 100 Redondo Canyon $ the transport and fate of the 50

90 20 80 contamination

100 Palos Verdes 200 Palos Verdes Peninsula 70 Point $ current risk to human health and the 300 400 500 environment from the site. 600 Portuguese Bend Landslide

700 Pt. Vicente Although discharge of DDT and PCBs Los Angeles Harbor stopped over 30 years ago, these persistent

shelf pollutants remain in the sediment off Palos White Point slope Pt. Fermin Verdes Peninsula. The RI found the quantity

shelf LACSD outfalls 20 of DDT and PCBs has dropped over the 800 slope 50 years. Some of the contaminants have been Palos Verdes shelf break Shelf Site carried off the shelf into deeper waters, some 33 40’ have been diluted by mixing with cleaner sediment, and within the contaminated sedi­ ment deposit we found evidence that DDT— North 0 2.5 5 KILOMETERS but not PCBs—is slowly breaking down. The Isobaths are in meters

70 RI report used new fish data to recalculate 80

100

200 300 the risk to human health posed by the site 500 400

600

700 and found that fish, especially bottom-feed­ 800 ers like white croaker, still contain levels of Point Conception DDT and PCBs that warrant fish advisories Los Angeles (see Table 1, Pg. 7). The site still poses a

Southern Site threat to wildlife in the area as well, although California Bight San Diego Figure 1: Palos Verdes we have seen some indications of recovery, Southern California Superfund like bald eagles nesting on the Channel Is­ Study Area lands. ES102006019SCO335398.RR.01 PVS_009.ai 12/06 EPA has been addressing the immediate threat to human is a small but prominent land mass extending into the South­ health by working with state and local agencies as well as ern California Bight. It is bordered by Santa Monica Bay to community groups to reduce consumption of fish species the north and the San Pedro Shelf to the south. The Chan­ most likely to contain high concentrations of contaminants. nel Islands lie to the west and northwest. The narrow un­ The Institutional Controls program is described on Page 4. derwater shelf off the Palos Verdes Peninsula is called the Concurrently, EPA began the Superfund process of investi­ Palos Verdes Shelf. It is approximately 9 miles long and gation, risk assessment, and remedy selection. less than 1½ miles wide. The seabed over most of the shelf slopes at a gentle 1 to 3 degrees. The shelf breaks at a This fact sheet summarizes EPA’s Remedial Investigation depth of 250 to 300 feet, then drops steeply over 2,300 feet (RI) Report that presents our current understanding of con­ to the ocean floor. (See Figure 1.) ditions in the Palos Verdes Shelf Study Area. The full RI Report for the Palos Verdes Shelf Superfund Site is avail­ A 1933 study of the Palos Verdes Shelf characterized it as able online at EPA’s Region 9 website: an area of rocky outcrops and kelp beds. Since then, ur­ www.epa.gov/region09/waste/sfund/pvshelf. banization, the Portuguese Bend Landslide, and the White Point outfalls have changed that. From the 1930s through Following the RI, EPA will formulate potential remedies to the 1980s, the White Point outfalls have discharged onto the reduce the risk to human health and the environment posed shelf about 4 million tons of sediment. North of the outfalls, by the site. These alternative remedial actions will be de­ the Portuguese Bend Landslide has contributed an esti­ scribed in a Feasibility Study, scheduled to be released for mated 6 to 9 million tons of sediment onto the shelf since public review in Fall 2008. EPA will describe its preferred the 1950s. Engineering measures have stabilized the land­ alternative in a proposed plan that will be available for com­ slide; nevertheless, the toe of the landslide continues to ment at public meetings in the San Pedro/Palos Verdes erode and act as a source of sediment. Peninsula vicinity. The current and wave patterns along the Palos Verdes Site Characteristics Shelf vary by season and location. Figure 2 shows the general flow patterns for the Southern California Bight. The California coast from Pt. Conception to the Mexican Dominant ocean circulation patterns include the southward- border curves inward, forming a large bay called the flowing California Current, the northward-flowing California “Southern California Bight.” The Palos Verdes Peninsula Countercurrent, and seasonal influences by the northward-trending Davidson Countercurrent. Surface and bottom

SANTA BARBARA waters are typically separated in spring through fall by a pycnocline (a zone of rapid change in seawater density) occur­ ring at depths of 30 to 100 ft. Currents below the pycnocline on the shelf gener­ 200 Pt Dume ally flow to the northwest, parallel to Santa Monica seabed contours. In contrast, surface 200 currents flow predominantly southeast­ ward, although they shift to a westerly 200 500 500 flow in late autumn and early winter SAN PEDRO Newport 200 1000 Beach when westerly winds weaken. Most of the time, near-bottom waves and cur­

200 rents do not resuspend sediment; how­ San California Clemente ever, episodically, primarily during

200 Countercurrent 500 500 storms, currents and waves resuspend

California 1000 and move sediment across and off the

500 Current 1000 1000 shelf. System 500 1000

W 46048

Figure 2: General flow patterns for the Southern California Bight

Page 2 Palos Verdes Shelf Superfund Site February 2008

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D PointPoin t VVicentei cente D D D D D D D SURFACE SEDIMENT (0 - 2 CM) D D CONTOURS OF DDTs, 0-200 M WATER - DEPTH (mg/kg DW) D 60 PPointoint D D D FFerminerm in D Sediment Sample Locations D D Outfall s D Outfalls -8 D 00 D 0- 0.05 D D D 0.05- 0.1 0.1- 0.2 -800 D D -1 00 0.2- 0.5 D 0.5- 1 D 1-1.5

800 1.5- 3 - 3-10 D -80 10- 25 ³ 0 D 25- 50 50- 90 90- 155 0 - -80 800 0 1.5 -500 Miles -700 -600

Figure 3 (DDT deposit map): The effluent-affected (EA) deposit is over 2 feet thick and has surface DDT concentrations of 200 ppm (parts

Page 3 per million) at the outfalls. As the deposit fans out to the northwest, surface contaminant concentrations drop to 2 to 10 ppm, with concentra­ tions less than 1 ppm closer to shore and 3 to 15 ppm over the shelf break. Beneath this top layer of 6 to 12 inches, the sediments contain contaminant concentrations in the 100 to 200 ppm range. Why are there tons of DDT and PCBs on Palos Verdes Shelf? Institutional Controls Program Los Angeles County wastewater (effluent) has discharged The Institutional Controls (ICs) program was put at White Point off the Palos Verdes Shelf since 1937. Sew- in place to address the human health risks as­ age is treated at the Joint Water Pollution Control Plant in sociated with consumption of certain fish, such the City of Carson before it enters the outfalls. The Los as white croaker, caught off the Palos Verdes Angeles County Sanitation District (LACSD) is in charge Peninsula that typically contain high concentra­ of the county’s sanitation system. Among the many indus- tries that used the sewer system was the Montrose Chemi- tions of DDTs and PCBs. The ICs program has cal Corp., the nation’s largest manufacturer of DDT. From three components: public outreach and educa­ the 1950s to 1971 tons of DDT and associated manufactur- tion, fish monitoring, and enforcement. The pro­ ing waste entered the sewer system to be discharged ulti- gram relies on partnerships with other federal, mately from the outfalls at White Point. In 1971, the last state and local agencies and community-based year Montrose used the county sewers, an estimated 50,500 organizations to enforce the commercial catch lbs. of DDT were discharged from the outfalls. PCBs, an- ban and bag limit on white croaker and to edu­ other persistent hazardous substance, also formed part of cate the public on fishing practices and fish the industrial waste stream that was discharged to the preparation methods that minimize exposure to sewer system until their ban in 1976. After these persistent contaminants. Information about the ICs program pollutants ceased to dominate the waste steam, LACSD can be found online at www.pvsfish.org. continued discharging treated waste onto Palos Verdes Shelf. This created a layer of cleaner sediment on top of the DDT- and PCB-contaminated sediment.

On the Palos Verdes Shelf, an estimated 5.7 million tons of sediment have been affected by the effluent discharged from the White Point outfalls. Mixed within these effluent- affected (EA) sediments are an estimated 110 tons of DDT and 11 tons of PCBs. The EA sediment forms an identifi- able deposit over a mile offshore at a depth of 150 feet to their importance for different parts of the shelf. Below are the shelf break. The deposit ranges in thickness from 2 brief discussions of the biological, chemical, and physical inches to over 2 feet, with the area of greatest accumula- processes that control the fate and transport of the EA sedi- tion at 200 feet. It is thickest and has the highest concentra­ ment. tions of DDTs and PCBs in the vicinity of the outfalls, then Biological fans out to the northwest. See Figures 3 and 4 . The roughly 1 foot of cleaner surface sediment covering the more contaminated layer still contains measurable concen- Fate and Transport of the EA trations of DDT and PCBs. How are the buried contami- Sediments nants reaching the surface? One explanation is biological. The shelf floor is home to worms, sea cucumbers, shrimp, As stated earlier, discharge of DDT and PCBs onto Palos crabs and other invertebrates. Many of these pollutant-tol- Verdes Shelf stopped in the 1970s and discharge of total erant creatures turn the sediment just as earthworms work suspended solids had been reduced 97 percent by 2003. topsoil. Although most of the mixing occurs in the top 6 Concentrations and quantities of DDT and PCBs in the EA inches, some larger species, such as ghost shrimp, can bring sediment appear to be less today than in 1992. The EA de- up buried sediment from several feet below the surface. posit is buried under cleaner sediment; one of the questions This vertical mixing adds DDT and PCBs to the surface that will determine how best to deal with the remaining con­ sediments. The mixing also loosens the material, making it tamination is will the deposit stay buried? The RI Report more susceptible to resuspension. However, the inverte- examines the various processes that affect the EA sedi- brates also consolidate sediment as they eat its organic mat- ments, discusses how they interact, and attempts to quantify

Page 4 Palos Verdes Shelf Superfund Site February 2008

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-4 -50 00 0 -6 00 PALPALOS VERDESVERDES D PENNINSULAPENNINSULA -70 D 0 D PoPoiintn t ViVi ccenteente D D D D D D D D SURFACE SEDIMENT (0 - 2 CM) D -6 CONTOURS OF PCBs, 0-200 M WATER D 0 D PPointoin t DEPTH (mg/kg DW) D D FFerminerm in D Sediment Sample Locations D D D Outfalls D Ou -800 D tfa 0- 0.05 D lls D D 0.05- 0.075 -800 -800 D 0.075- 0.1 D -10 D 0.1- 0.15 0 0.15- 0.2 D

0.2- 0.3 0

0.3- 0.5 -80 0.5- 0.75 D 0.75- 1 ³ D 1- 1.25 1.25- 1.5 1.5- 2 - -800 800 0 1.5 -500 -600 -600 Miles

Page 5 Figure 4 (PCBs map): Surface concentrations of PCBs are typically less than 0.5 ppm except in the vicinity of the outfalls. Recent data on PCB concentrations at depth are not available; however, in 1992, the concentrations a foot or more into the deposit ranged from 2 to 20 ppm. ter and produce fecal pellets. A 1992 study found as much ucts have been identified in these cores, as well. However, as 50 percent of the silt and clay fractions of the EA sedi­ very little is known about the toxicity of these breakdown ment had been pelletized. products. Reductive dechlorination would explain the reduc­ tion in DDE concentrations that are seen at depth in the de­ Chemical posit. However, chemical analyses of sediment cores Most of the DDT on Palos Verdes Shelf converted quickly across the shelf would be required to determine if and to to DDE or DDD, two DDT-related compounds. Recent what degree this transformation is occurring. There is no analysis indicates that, at least in some areas, the chemical evidence that PCBs, originally deposited on the shelf as in­ breakdown process is continuing. EPA has limited but com­ dustrial chemicals called “Aroclors,” are undergoing reduc­ pelling data on the occurrence of this process, called reduc­ tive dechlorination. The observed loss of PCBs can be tive dechlorination. Sediment cores collected in1992 off attributed to dispersion. Long Pt. at the 200 ft. depth were compared to cores col­ lected from the same location in 2005. Analysis of the Physical cores shows DDE is transforming into another a simpler, Waves and currents suspend, deposit, and transport sedi­ related chemical called DDMU. Other breakdown prod­ ment along and away from the shelf. When the finer and more organic particles that make up the EA sediment are suspended, the 118 30’ 118 20’ contaminants they contain are trans­ ported along with them. If more sedi­ Santa Monica Bay ment is transported into an area than 33 50’ LOS ANGELES is transported out, sediment will accu­ COUNTY 8 mulate. This tends to bury the existing EA sediment, which appears to have 100 Redondo Canyon happened north of the outfalls. The 50 90 Zone 3 9 20 opposite occurs if sediment transport 80

100 Palos Verdes out of an area is higher than the rate 200 Palos Verdes Peninsula 70 Point 300 400 of transport in; in which case the con­ 500 E 600 taminated sediment is eroded. The 10 area southeast of the outfalls appears Portuguese Bend 700 Pt. Vicente Landslide Los Angeles to be erosive. Material resuspended Harbor 11 12 from the EA deposit, especially slowly settling particles, can travel off the Zone 2 White Point Palos Verdes Shelf before settling Palos Verdes 13 Pt. Fermin Shelf Site LLACSDA back to the bottom. Individual par­ outfallso 1420 ticles may undergo the process of 800 Zone 1 15 50 resuspension, transport, and deposition many times and will gradually disperse 33 40’ B from the shelf, typically ending up in on the slope or in the deeper basins where they are resuspended less fre­ quently. The top layer of sediment is 0 2.5 5 KILOMETERS most affected by these processes. Isobaths are in meters Over time, the fine sediment is win­ 70

80 100 nowed out, leaving coarser, heavier - EPA Sampling Location 200 300 500 400 sediment, less susceptible to 600

- LACSD Fish Sampling Zone 700 resuspension by waves and currents. 800 12 - MSRP Fish Sampling Segment

Figure 5: Palos Verdes Shelf fish sampling locations

Page 6 Palos Verdes Shelf Superfund Site Human Health and dose to quantify potential noncancer health effects. A hazard quotient of 1.0 is considered the threshold to indicate Environmental Risks an exceedance of the reference dose. EPA assumes there Reassessed is no safe exposure threshold for carcinogens; therefore, EPA calculates risk from probable carcinogens as potential EPA prepared a Human Health Risk Evaluation in 1999 increased cancer risk over a lifetime. using fish data from multiple sources and years. For the RI Report, EPA used more recent data from the 2002 EPA- In reassessing human health risk for the RI Report, EPA Montrose Settlement Restoration Program Joint Ocean Fish used two consumption scenarios: a reasonable maximum Survey and from LACSD’s 2002 fish sampling (see exposure (RME) (i.e., consumption) of 107.1 grams of fish Figure 5) to reassess the human health risk. The harm a day and for high end consumers, 115.7 g/day (about a posed by the site is in the transfer of contaminants from the quarter pound of fish a day). The other scenario, called a sediment into the food chain. Fish accumulate DDTs and central tendency exposure (CTE), represents a more varied PCBs when they eat worms, crabs and other creatures diet, where fish consumption would equal 21.4 g/day (one living in the sediment. The reassessment analyzed DDT and 5-ounce serving a week). Table 1 shows potential health PCB tissue concentrations found in six species of fish risks under these scenarios for each of the six fish. It is collected from the Palos Verdes Shelf Study Area: kelp worth noting that these health risks used DDT and PCB bass, white croaker, barred sandbass, rockfish, surfperches, concentrations found in fish tissue only. Both DDT and and California scorpionfish. PCBs are lipophilic, i.e., they accumulate in fat. Therefore, whole fish concentrations are typically 8 to 10 times higher Both PCBs and DDT are known to have deleterious health than tissue concentrations. As a result, these risk values effects and are probable human carcinogens. EPA uses a underestimate exposure for people who consume whole Hazard Index developed from a daily exposure or reference fish, such as in stews and other dishes.

Reasonable Maximum Exposure Central Tendency Exposure Noncancer HQ Fish Species Cancer Risk Noncancer HQ Cancer Risk (>1 exceeds reference dose) (>1 exceeds reference dose)

White Croaker 6 x 10-3 183 6 x 10-4 37

Kelp Bass 1 x 10-4 5 1 x 10-5 0.9

Rockfish 1 x 10-4 5 1 x 10-5 0.9

Surfperch 7 x 10-5 2 6 x 10-6 0.5

CA Scorpionfish 3 x 10-4 8 3 x 10-5 2

Barred Sandbass 3 x 10-4 10 3 x 10-5 2

Table 1: Cancer and noncancer health risks based on the 95 percent UCL (upper confidence limit) of the mean concentration of contaminants found in these six species of fish caught from the Palos Verdes Shelf Study Area. The Reasonable Maximum Exposure assumes a consumption rate of about a meal a day. The Central Tendency Exposure assumes a consumption rate of about a meal a week.

February 2008 Page 7 Palos Verdes Shelf Superfund Site Update Site Contacts: Carmen White, SFD-7-1 Jackie Lane, SFD-3 Remedial Project Manager (Remedial Community Involvement Coordinator Investigation and Cleanup) (415) 972-3236 (415) 972-3010 [email protected] [email protected] U.S. EPA Region 9 Sharon Lin, SFD-7-1 75 Hawthorne Street Remedial Project Manager (Public Outreach and San Francisco, CA 94105 Education, Monitoring and Enforcement) (415) 972-3446 Toll Free Hotline: [email protected] (800) 231-3075

For more site information, visit the Region 9 Superfund Site overview page at http://www.epa.gov/region09/waste/sfund/pvshelf.  For Site Repository locations, check the Site overview web page above.

United States Environmental Protection Agency FIRST-CLASS MAIL Region 9 POSTAGE & FEES 75 Hawthorne Street (SFD-3) PAID San Francisco, CA 94105 U.S. EPA Attn: Jackie Lane (PVS 12/07) Permit No. G-35

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